A railway is typically formed by laying wooden cross ties at spaced intervals and fixedly attaching a pair of rails thereto. The ties are typically laid on a layer of crushed rocks or gravel.
For example, U.S. Pat.No. 2,623,300 granted to M. S. Hudson discloses a railroad tie having a tie plate recess or dap for accommodating a tie plate. The dap is provided with spaced holes for receiving tie plate spikes. The spikes may then be driven through the holes.
U.S. Pat. No. 3,588,049 granted to Charles J. Pennino discloses a tie having a shallow recess for a tie plate under which a plurality of reinforcing members are driven into predrilled holes passing only through the tie. A rail rests on a tie plate and both are secured to the tie by driving spikes therethrough.
U.S. Pat. No. 4,202,494 granted to James A. Rummel discloses a typical rail line using ties to which the rails are secured by bolts.
U.S. Pat. No. 4,349,151 to Schumaker discloses several embodiments of a bent steel rod holding device for securing a rail and tie plate to a tie.
As cross ties are made of wood and exposed to the harsh natural environment, they need to be treated so that they resist splitting and/or rotting. It is desirable to use hardwood due to their durability and strength characteristics. However, it has been found that normal preservative treatment methods do not completely effectively treat wood, especially hardwood, as the preservatives cannot penetrate adequately throughout the tie. This is especially true when measured against the requirements set forth in the American Wood Preservers' Association which requires at least 3" penetration to adequately preserve the wood.
Attempts have been made in the past to prevent wood from splitting during the curing or drying phase, as disclosed for example in the aforementioned Hudson patent. Hudson provides staggered holes which are drilled vertically or horizontally through the tie, adjacent its ends for purposes of allowing moisture from the center portion of the tie to be released therethrough instead through the ends of the tie.
Hudson, however, does not contemplate any means for permitting preservatives to penetrate into the wood, especially hardwood, and for preventing propagation of cracks or splits in the tie that are developed as a result of exposure to the environment.